Selector system



0, 1949. A. H. BARNARD ET AL 2,430,524

SELECTOR SYSTEM Filed Jan. 2, 1947 1N VEN TORS 1 2e 66 44 VW A. 54RN4RDE BY ARNOLD M. SKUDRE Patented Aug. 30, 1949 M. Skudre, Somerset,Mass.,.assig.nors tmRagym theon: Manufacturing Company. a corporation oiDelaware Application J anuary' 2, 1947; SeriaFNn'fiQSM? 4 Claims. (Cl.111-353) Thepresent'inventionrelates tc codesresponsive:

electric circuits andmore'particularlyto an el'ecti'ic circuit which maybe termed a codedselective ringing circuit and which is adaptedto en'--ergize an output load only after application to itsinput terminals of aplurality. of series of electriccurrent pulses of a predetermined numberand in. predetermined: series sequence.

It is an. objectof this invention to provide an improved coder-esponsive electric circuit. having a pairrof input terminalsandanzoutput load circuit; together with means in thecircuitturespond-to a;- plurality' of series: of electric current pulsestochargea: first storage deviceupcrr application-to. the-inputterminalsofiazpredeterminedinumber 'of pulses in a first series of pulses, to;chargeasedondistorage device in. accordance with the charge;

of: the. first device upon application of a'predetermined' number ofpulses irra second series of:

pulsesgyand' to; energizetheload circuit by connectingthe'secondstorage. device-to thezload'upon. application of a: predeterminedanumberof pulses:

in-a third seriesof pulses.

It'is also ancbiect of" thisinventioni. to provide arr; improved. codevresponsive electric circuit of; the aforementioned type having cnlyasingletbanlc' stepping selector. switch'fcr: controlling thechargingof: the: storage devices and the energization.

of the load :circuitin" response tc'the pluralityof series: ofpredetermined electric. pulses applied in;

predetermined sequence to. theinputiterminals:

The series :of electric pulses may-beyobtained loyintermittentlyconnecting a source of electric current tothe input terminals. of thecircuit. A telephone dial; mechanism is especially suitable fon'thispurpose. The conventicnalidial mechanism. would connect the electriccurrent'totheirrputaterminalsyin a mannertorproduce pulses. oi.

uniform: pulse. duration and" uniform pulse interval, the frequency: ofpulses being of ap-- proximately eight pulses per second. When: ole--tainingJa plurality of. series of pulses from. such mechanism it is.usual; that the-time interval between each series of." pulses of apredetermined 2. cfithe circuitupcnapplicationzof a predetermined numberof. pulses in eachseries of pulses.

objects and advantages will be ap.--

parent upon reference-to: the-following specifica- 1f tionand:drawing-fin. which the. single figure of the drawing; isa schematic:diagram: of the code. i re sponsive circuit of this invention.

Referring; tothe drawing, theseries of pulse.

signals; are applied to the; input terminals Ill and it connectedbetween. the grid. and: cathode,

ofaan; electrorrtube I2; The: plate oftube I2 is:

connectedth-roughthe coil Ht f: a. relay l3 toithe positive: terminal,oi: at plate supply- ]catteryl5 whose negative. terminal.- is groundedasis also:

s the cathode of. tube; I2. Tube l-Z may be of anysuitable type, suchas, for example, the triode. type-1L4.andetheyparameters of the tube.and its circuitare such-that. the tube is-normally biased tc' cuteofiithe. grid battery. 9; the absence 2f} 0L an: electric pulse signal ofpositive polarity applied -tuthe terminals l (1 and. H andconversely isconductive-whenever such. a pulse signal is. a-.p.-

plied. Thus the plate circuit relay l3 isener.-

sized whenever anelectric pulsecf proper polarisrapplied tathe. inputterminals in. and H. Relay'l3 is: provided. with a pair. of normally.open. contacts 46; and. lil which: are. adaptedto Ice-closed.upomenergization of the relay. Con.- tact. Iii-of. relay l3- is groundedas. shown and ccntachl'l is.-connected-.by line la through the coil laoiratchet-irelay z ll toline .2 I; through con.- tact 22 and switch arm23 of the three-pole double-throwrrelay '24 and lay line 25:;to-apositiveterminal 2.6. or aibattery 2.1 whcse negative terminal isgrounded. to' complete the.- circuit throughanon-uii switch 28. The;three-pole double-throw relay Mai-s. shown; in the energized positionand with its. contactsin:suchpositionitwill'be seen that theratchetre'lay' 20c Willbe'energized I Wheneverrelay I a/is. energized to close;its contacts I 6 and I l upcnapplicatiomof an electric pulse of;properpolarity; to -the :inputhterminals; I it and I I.

Ratchet relay 20 is.-: provided with a ratchet arm orarmaturegiltengagingraratchet wheel 3-!- reater than the. interval oftime be? i fixed-ztmthezrotarwshaitsz' ora-single-bankrotary tween eachpulse in aseriesof pulses;

Itxis. therefore aiurther object ofxthisi ill-1V8? tion'to provide acode responsive'electric circuit adapted. to energize unload.- circuitin response tu the application toits input-terminals ofjaiv phrrality ofseries of electric. pulses havingapredetermined' number and. apred-eterminediseries se quence; the; circuit having means responsivedurlngthetimeiinterval"between'aeaclrseries of pulsesstepping; selectorswitch 33.

wiper armwflfii. The wiper arm iselectrically connected with the contactarm 34 and; itsrend' fortperiormmg theerequirech sequential operation:33..with:-a:selectedzonelfi'therequallyspacedcon- Also mounted on. the:shaft 32is;acontact: selector arm:34 and-a tacts 38-47. The ratchetrelay 20 having the ratchet arm 39 in engagement with the ratchet Wheel3| is so designed that each time it is energized the shaft 32 is therebyrotated to move the selector arm 34 through an angular distance equal tothe distance between the starting position and the first contact 38 orbetween each of the contacts 38-41.

A spring 48 is provided to urge the shaft 32 to rotate in acounter-clockwise direction back to the starting position but thelocking armature 49 of a reset relay normally engages the ratchet wheel31, as shown, to prevent such counterclockwise rotation of the shaft 32.Thus, each time the ratchet relay 29 is energized, the shaft 32 will beclockwise rotated by an amount suflicient to step advance the contactselector arm 34 from either the starting position to contact 38 or fromone of the contacts 38-47 to the next of said contacts. The Wiper arm 35attached to the shaft 32 is also moved clockwise coincident with themovement of the contact arm 34 and there by connects a selected one ofthe contacts 38-41 to the commutator section 36.

Also carried by the shaft 32 is a cam member 5| having an insulated camsurface 52 adapted to engage the spring contact arm 53 and cause it tomake electrical contact with the fixed contact 54. Contacts 53 and 54constitute a normally open switch but the cam 5! is so positioned on theshaft 32 that, whenever it is rotated to move the rotary switch contactarm 34 to a position engaging one of the contacts 384l, the cam surface52 will be caused to engage the spring contact 53 to close the circuitbetween contacts 53 and 54. 7

One terminal of the coil 55 for the reset relay 5!] is grounded and theother terminal is connected by line 56 to contact 51 of the three-poledouble-throw relay 24. When the relay 24 is deenergized from theposition shown, the contact 51 is connected by switch arm 23 to line 25and the battery 21 to thus energize the reset relay and disengage thelocking armature 49 from the ratchet wheel 3| to permit the shaft 32 torotate counter-clockwise in response to the spring 48 back to thestarting position shown. Energization of the reset relay 50 causing afull travel of the armature 49 also moves the spring contacts 58 and 59from their normally closed position to the open circuit position forreasons to be later referred to.

One terminal of the relay coil 59 for the threepole double-throw relay24 is grounded and the other terminal is connected through a resistance6! to line 62, through a pair of normally closed contacts 63 and 64associated with the relay 65 to line 53 and positive terminal 61 ofbattery 21. Thus the three-pole double-throw relay 24 is maintained inthe normally energized position shown so long as the relay 65 isnormally deenergized in its position as shown. A high capacity condenser19 is connected across the relay coil 65 to ground and due to theeffects of its stored energy prevents the relay 24 from assuming thedeenergized position immediately after the energization of relay 65 andthe breaking of the circuit to relay coil 60 through contacts 63 and 64.

The time constant of the condenser relay circuit 10, 60 is selected tobe a predetermined time interval long enough to permit the propercharging of condensers 89 or 9| as will be later referred to in adescription of the operation of the circuit.

One terminal of the relay coil II for relay 65 is grounded and the otherterminal is connected through resistance 12 to line 13 and springcontact 53 which when closed with contact 54 connects through lines 14and 66 to a positive terminal 61 of the battery 21. A condenser 15 isconnected across the relay coil H to ground and the constants of thecircuit, including the relay coil H, resistance 12 and condenser 15, aresuch that the condenser 15 will not be sufiiciently charged so that therelay 65 will be energized until after a predetermined time followingthe rotation of the shaft 32 and the closing of the contacts 53 and 54by the cam surface 52. Furthermore, the ungrounded terminal of relaycoil H is also connected through line 16 to a switch arm ll of anormally open switch having a grounded contact 78. Thus, whenever theratchet relay 23 is energized during the application of a pulse to theinput terminals I0 and H, the ratchet arm 30, on the end of which is aninsulated striker 19, will move the switch arm 11 into engagement withthe grounded contact 18 upon full travel of the ratchet arm 30 todischarge condenser 15 and short circuit relay coil ll.

Upon review of the circuits thus far described, including the circuitfor energizing the relay coil H of relay 55, it will be seen that therelay 65 is.

normally deenergized at the beginning of a series of pulses while therotary stepping switch is in the starting position. When the first pulseof a series of pulses is applied to the input terminals ID and H, therelay 65 is deenergized and relay 24 is energized to the position shownand the shaft 32 is rotated counter-clockwise to the contact position 38corresponding to the application of one pulse. At this time the camsurface 52 has closed contacts 53 and 54 so that the condenser l5 shouldstart to charge. However, during the duration of the pulse, the ratchetarm 30 is energized to close switch arm I! with grounded contact 18 andshort circuit condenser 15. At the end of the pulse duration an intervalbetween pulses occurs, which interval is of a selected duration as hasbeen previously described. During the pulse interval the ratchet arm 30is in the deenergized position and switch contacts I1 and 18 are open,removing the short circuit across condenser I5 and permitting it tocharge from the battery 21 through lines 65, '14, contacts 53 and 54,line 73 and resistor 12. If the pulse interval is greater than theselected pulse interval as would occur at the end of a series of pulses,the condenser l5 would become fully charged, thus energizing relay 65 toopen the normally closed contacts 53 and 64 and thereby deenergize relay6!] which would in turn move the switch arm 23 to contact 5! andenergize the reset relay 50 for permitting the shaft 32 and contact arm34 to move counter-clockwise back to the starting position shown. Shouldthe second pulse be received after no longer than the selected pulseinterval, however, the ratchet arm 35 would advance the switch arm 34 tothe second contact position 39 and again close contacts 11 and 18 toshort circuit the relay coil H and discharge the condenser '15 of itscharge thus far acquired without permitting the energization of relay 65which would have ultimately resulted in the energization of the Contactis denser 89, the second series of pulses transferring the charge ofcondenser 89 to condenser 9i, and the third series connecting thecharged condenser to the grid of the thyratron 99. As a furtherprotection against undesired operation of the output thyratron, the timeconstants for condenser-s 89 and 9| as determined by the resistances oftheir respective resistors its and Ill may be suitably correlated withthe total time interval for the three pulse series, including theintervals between pulse series and the pulse intervals, together withtotal number of pulses so that there will be insufficient charge left oncondenser 9! for firing the thyratron 99.

In the event that a Wrong number of pulses in the first series of pulsesis applied to the input terminals ill and H, the selector arm 34 will bereturned to the starting position without enabling the charging of thefirst condenser 89. Should more than the predetermined number of twopulses be applied, the contact selector arm 34 will have paused atcontact 39 for only the time interval equal to the pulse duration andthe pulse interval which as already noted is not sufficient time equalto th time interval between pulse series to permit condenser i and relay65 to be energized so that relay 24 may be deenergized for connectingthe contact 35 with the condenser 89. Similarly the second series ofpulses must be of the correct predetermined number in order that thefirst condenser 89 may be connected with the second condenser 9!regardless of whether the first condenser 89 has been previously chargedin response to a correct number of pulses in the first series of pulses.Finally, the correct predetermined number of pulses in the third seriesof pulses must be applied to connect the second condenser 8! with thegrid of the thyratron tube 99 which if the preceding two series ofpulses have been of the predetermined number and sequence will havesufficient positive charge to fire the thyratron tube SS3 and supply thesignal at the output terminals Hi2 and 5533. In order to reset thesystem after the thyratron 99 has been fired, the on-ofi switch 28 maybe moved to the open circuit position which will thereby stop conductionin the thyratron tube.

As specifically described, the circuit has been shown to respond to theapplication of three series of pulses comprising two pulses in the firstseries, five pulses in the second series and eight pulses in the thirdseries. In order to change the coded number of pulses to which thecircuit will respond, it is only necessary to reconnect lines 9%, 92 and9 3 with different selected ones of the contacts 38-47 corresponding tothe new selected numbers of pulses in the series of pulses. Changing theconnection of line 92 will change the predetermined number of pulsesselected for the first series of pulses and changing the connection ofline 95 will correspondingly change the predetermined number of pulsesin the second series of pulses to which the circuit will respond, whilechanging the connection of line 94 will change the predetermined numberof pulses in the third series of pulses. The contacts 38-41 have beenshown to be a part of a single bank rotary stepping selector switch butit should be understood that any form of single bank stepping selectorswitch may be used other than the rotary type shown. For example, alinearly moved stepping switch may be used equally as well in thecircuit of this invention.

Of course it is to be understood that this invention is not limited tothe particular details as described above as many equivalents willsuggest themselves to those skilled in the art. For example, other formsof electric storage devices, such as chokes, may be used instead of thecondensers referred to. Also, it should be obvious that electron tubesmay be substituted for the various relays and switches to perform thenecessary sequential functions in the system of this invention. It isaccordingly desired that the appended claims be given a broadinterpretation commensurate with the scope of this invention within theart.

What is claimed is:

1. In a code responsive circuit having a step selector switch, a sourceof voltage, first and second charge storage devices, a relay having anormally open switch and a normally closed switch, means to operate saidstep selector switch to first, second, and third positions in responseto three difierent pulse series representing a code, circuit meansconnecting said first charge storage device to said source via saidnormally closed switch and said step selector switch in said firstposition, circuit means connecting said second charge storage device tosaid first charge storage device via said normally closed switch andsaid step selector switch in said second position, output terminals,circuit means arranged to connect said second charge storage device tosaid output terminals via said normally open switch and said stepselector switch in said third position, and means to operate said relayto open said normally closed switch and to close said normally openswitch.

2. In a code responsive circuit having a step selector switch, a sourceof voltage, first and second charge storage devices, a relay having anormally open switch and a normally closed switch, means to operate saidstep selector switch to first, second, and third positions in responseto three difierent pulse series representing a code, circuit meansconnecting said first charge storage device to said source via saidnormally closed switch and said step selector switch in said firstposition, circuit means connecting said second charge storage device tosaid first charge storage device via said normally closed switch andsaid step selector switch in said second position, output terminals,circuit means arranged to connect said second charge storage device tosaid output terminals via said normally open switch and said stepselector switch in said third position, and

means to operate said relay to open said normally closed switch and toclose said normally open switch after a prescribed interval followingthe setting of a complete series of pulses into said step selectorswitch.

3. In a code responsive circuit having a step selector switch, a sourceof voltage, first and second charge storage devices, a relay having anormally open switch and a normally closed switch, means to operate saidstep selector switch to first, second, and third positions in responseto three different pulse series representing a code, circuit meansconnecting said first charge storage device to said source via saidnormally closed switch and said step selector switch in said firstposition, circuit means connecting said second charge storage device tosaid first charge storage device via said normallyclosed switch and saidstep selector switch in saidsecond position, output terminals, circuitmeans arranged to connect said second charge storage device to saidoutput terminals via said normally open switch and said step selectorswitch in said third position, a second relay having a second normallyopen and a second normally closed switch, said second normally openswitch being included in common in all said circuit means, said secondnormally closed switch being included in the energizing circuit of saidfirstmentioned relay, means to operate said second relay to close saidsecond normally open switch and open said second normally closed switch,said first-mentioned relay being operative when deenergized to open saidfirst-mentioned normally closed switch and to close said first-mentionednormally open switch, and means providing a time delay in thedeenergization of said firstmentioned relay.

4. In a code responsive circuit adapted to provide an output signal inresponse to the receipt of a pluralit of series of electric pulseshaving a prescribed number of pulses in each series, a step selectorswitch having a single bank of selectively engaged contacts and a maincontact adapted to be connected successively to one after the other ofsaid selectively engaged contacts when said switch is operated, firstand second storage devices, first, second, and third code contactsconnected each to a difierent one of said selectively engaged contactsin accordance with a prescribed code of which each digit corresponds tothe number of pulses in one of said series, a Source of voltage, a relayhaving a normally open switch and a normally closed switch, circuitmeans including said first code contact and said normally closed switchconnecting said first storage device to said source via said stepselector switch, circuit means including said second code contact andsaid normally closed switch connecting said first storage device to saidsecond storage device via said step selector switch output terminals,circuit means including said third code contact and said normally openswitch arranged to connect said second storage device to said outputterminals via said step selector switch, and means to operate said relayto open said normally closed switch and to close said normally openswitch after a prescribed interval following the setting of eachcomplete series of pulses into said step selector switch.

ALVIN H. BARNARD.

ARNOLD M. SKUDRE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,063,354 Thorp Dec. 8, 19362,168,198 Frank Aug. 1, 1939 2,441,145 Hansen May 11, 1945

